The core body temperature of the average adult human is normally about 98.6° Fahrenheit (about 37.0° Celsius). However, body temperatures vary depending on certain conditions such as physical activity, environment etc. Humans have trouble adapting to extreme temperature conditions.
If you're partaking in physically exerting activities in a hot environment, or even just exposed to a hot environment for a prolonged period of time, your body temperature could rise to dangerous levels. If your body temperature reaches about 104° Fahrenheit (about 40° Celsius), you could experience heatstroke. Lowering your body core temperature for short periods of time can help you avoid heatstroke, improve sleep, or reduce a fever, but it's important to do so safely so that your body temperature is not reduced too much.
If you are exposed to a cold environment for a prolonged period of time, your body temperature could lower to dangerous levels. It's important that you conserve body heat and raise your core temperature to avoid organ failure and even death due to prolonged low body temperature. Only a three degree reduction in body temperature (about 95° F. (about 35° C.)) is needed to induce hypothermia. Raising your body core temperature for short periods of time can help you avoid hypothermia but it's important to do so safely so that your body temperature is not increased too much.
Change in body temperatures can also exacerbate medical conditions of existing patients. For example, a temperature increase can make many people with multiple sclerosis (MS) experience a temporary worsening of their symptoms. Doctors believe that this occurs because heat causes nerves (whose myelin covering has been destroyed from MS) to conduct electrical signals even less efficiently. Additionally, for reasons that are not well understood, decreases in body temperature can also cause MS symptoms, usually spasticity, to flare.
Attempts have been made to provide personal cooling devices. For example see U.S. Pat. Nos. 5,802,865 and 6,189,327, the disclosures of which are incorporated herein in there entireties by reference. These personal cooling devices are evaporative type devices that fit around a person's neck or head. Body heat is transferred away by a fan-induced flow of moistened air. While such prior devices may provide the user with some perception of cooling, they are ineffective at rapidly reducing the user's core body temperature and cannot lower temperature below room temperature. Additionally, these prior devices require the user to replenish a water supply which can be difficult or even impossible under some conditions.
Other attempts to provide a personal cooling or heating device utilize Peltier thermoelectric devices. For example see U.S. Pat. No. 6,125,636, the disclosure of which is incorporated herein in its entirety by reference. While such prior devices actively cool to provide the user with perception of rapid cooling or heating, these prior devices are designed to concentrate cooling the forehead or back of the neck. The area of the brain that senses and regulates body temperature is located in the base of the neck in an area of the brain called the brainstem. Cooling this spot down tricks the body into feeling like it is cooler than it really is. Thus, the process of cooling or heat may be stopped prior to adequately lowering or raising the user's body temperature. Additionally, using such inefficient cooling or heating spots on the body takes an undesirable amount of time to adequately lower or raise the user's body temperature.
Accordingly, there exists a need for a personal cooling and/or heating device that effectively and rapidly lowers and/or raises the user's body temperature.